Commands to electronic devices have typically been issued by pressing a button or flipping a switch. However, voice and other types of commands are becoming more prevalent in user interfaces, such as the voice-commanded dialing of cell phones. In such systems, a user may speak a command into a microphone to dial a friend's phone number, and the user may hear a beep or see a light flash to indicate that the phone is dialing the number. But if the cell phone's speaker is already being used, such as because the phone is playing a song, the cell phone may interrupt the music to play the beep, or, if sounds have been muted, it may not provide an acknowledgement to the user at all. Thus, it may be desirable to provide other mechanisms for providing responses to the user.